NH2-PEG4-Val-Cit-PAB-OH is a cleavable ADC linker featuring a primary amine, a hydrophilic PEG spacer, a Val-Cit dipeptide, and a PAB group. The benzylic alcohol on the PAB can be used to attach with reactive groups such as PNP for conjugation with drug payloads. The primary amine is free to perform a wide variety of reactions such as coupling with carboxylic acids, reductive aminations with ketones or aldehydes, or other more specialized uses such as in SNAr reactions or heterocyclic chemistry. The Val-Cit dipeptide is cleaved by cellular proteases within the cell to allow for efficient payload delivery via an elimination mechanism within the PAB structure.